The present invention relates generally to automotive radar systems, and in particular to a radar system for detecting when a moving vehicle of an adjacent lane is approaching a stationary vehicle from behind to prevent the opening of a door of the stationary vehicle whereby possible collision of the vehicle door when opened by a careless passenger against a passing vehicle is avoided.
When a vehicle passenger attempts to get off the vehicle on the side opposite to the sidewalk, he turns around or looks into the rearside mirror before he opens the door in order to ensure that there are no vehicles approaching it from behind to move past on the adjacent lane. However, there is a dangerous situation if the door is opened by a careless passenger when there is another vehicle approaching from behind. Such dangerous situations may also occur if the visibility of the rearside is limited so that the passenger has difficulty in ensuring the absence of any approaching vehicles from behind.